Police say the woman was walking west along John Street, west of Bayview Avenue in Markham, when she was struck by a Honda Accord at about 11 p.m. Tuesday.
The 59-year-old woman was taken to hospital.
The Honda driver was not hurt. Police say he is an 80-year-old man from Markham.
Anyone with information is asked to call investigators at 1-866-876-5423, ext. 7704, or Crime Stoppers at 1-800-222-8477.